Furnace liner



R. W. ULBRICH Nov. 1, 1966 FURNACE LINER Filed Jan. 3, 1964 UnitedStates Patent 3,282,578 FURNACE LINER Richard W. Ulbrich, 126 W. DixonAve., Dayton, hio Filed Jan. 3, 1964, Ser. No. '335,535 7 Claims. (Cl.263-40) This invention rel-ates to a liner for a Ifurnace, oven, kiln orthe like.

The heating industry in general has long been plagued with the problemof providing adequate furnace line-rs. The problem exists because thepresent materials used for linens for the most part are bulky and heavy.This, of course, is due to the fact that the primary consideration inproviding such a liner is to select a material .that can withstand thehigh heats which are required to be generated in the ovens in which theyare to be used. A comrnon example of such a liner is fire brick or somesuch refractory and/ or insulation used in most ovens in which heatsupward of 1000" F. are produced. The refractory of necessity must Ibebulky and heavy in order to withstand the required temperatures andrepeated exposure to thermal shock. Also, sin-ce the primaryconsideration of the refractory is to withstand the shock withoutspalling, additional insulation for the oven is necessary and whichmakes the outer shell of the furnace very lange -i and expensive inorder to support the weight of the refractory and insulation.

The heating device of the type ldescribed above requires in addition toa heavy, bulky wall structure, auxiliary apparatus such as forced airblower or the like to produce heats above approximately 800 F. becausethe present liners -are not capable of eicient radiation and re-radiation of the heat produced in the chamber.

The practical effect of the above drawbacks is to .make a furnace, oven,kiln or the like which is required to produce heats above approximately800 F. very .heavy 'and expensive, and requiring sizable areas on whichto locate same.

The present invention overcomes this long standing problem by providinga light in weight, efficient liner for ovens, kiln, or the like whichsubstantially increases the heat producing capacity of the oven in whichit is used; yet due to its light weight, does not require a heavy andbulky support wall as do the present liners.

It is therefore an object of the present invention to provide a novell-iner for a furnace, kiln or the like which is more efficient thanthose in the prior art.

An additional object of the invention is to provide a novel liner forovens, kilns or the like which is compact in size and light in Weight. J

Another object of the invention is to provide a novel liner `forfurnaces, ovens, kilns or the like which req-uires less supportingstructure due to its lighter size and weight.

An additional object of the invention is to provide a liner for =afurnace, oven, kiln or the like which renders the furnace capable ofproducing 'heats above approximately 800 F. without expensive, bulkyauxiliary heating apparatus.

Another object of the invention is to provide la liner comprising 'aplurality of screens in juxtaposition relationship to present greatersurface area to the heat produced in the heat chamber so that the heatmay be radiated and rie-radiated between the liner and furnace charge.

A further object of the invention is to provide a novel liner forfurnaces, oven, kilns or the like which comprises a plurality of screensin juxtaposition relationship wherein the inner layer of screeningadjacent the 'heat chamber is of coarser mesh than the layer furtherremoved therefrom to better withstand exposure to the highertemperatures.

3,282,578 Patented Nov. l, 1966 These and other objects will becomeapparent to one skilled in the art from the following description of theinvention taken in conjunction with the drawings in which:

FIGURE 1 is a cross-sectional view of a furnace showin-g the presentinvention used in conjunction with a typical furnace.

FIGURE 2 is an enlarged cross-sectional view of the wall of the furnacetaken substantially along lines 2 2 of FIGURE l showing a particularconstruction of the liner.

FIGURE 3 is an enlarged cross-sectional view of a furnace walldepicting. a modified liner that could be used in the environmentdisclosed in FIGURE l.

T-he general furnace combination is disclosed in FIG- URE l anddesignated by reference numeral 1. The furnace, oven, kiln or the likeconsists of an outside shell 9, a layer of insulation 8 adjacent to theoutside shell 9, and a liner 7, all supported on a base 6. Burners orheating elements 4 are positioned on the base and extend into a heatchamber 10. A grate or support means 3 is provided within chamber 10 tosupport a charge 2. Fuel or power lines S are provided to deliver lfuelor power to the :burners or heating elements 4. The type or number ofheaters used i.e., gas, oil or elect-ric is immaterial so far as thepresent invention is concerned.

The invention pertains to the construction and use of the liner in afurnace, oven, kiln or the like. The liner comprises multiple layers ofscreens arranged in juxtaposition relationship. The screen layers nearerto the charge 2 are generally, but not necessarily, of `coarser meshthan the layers more remote from the heat chamber 10 as illustrated inFIGURE 2. The reason for such an arrangement is so the screen nearer tothe heat chamber 10 can withstand greater heat with less deterioration,whereas the screens more remote are of finer mesh so that they canpresent a greater radiation surface per unit of screen area to radiatethe heat not radiated by the coarser screens closer to the heat chamber.Obviously, the finer the rnesh o-f wire used, the greater is theradiating surface per unit of screen. The most efficient liner would bewhere all layers of screens are of fine mesh. This arrangement, shown inFIGURE 3, would be practical where the oven, kiln, furnace or the likeis required to produce only ,relatively low 'heats in which the finermesh wire would be able to withstand the -lo-wer heats with only normalwear. Conversely, where relatively higher heats `are to be produced, theliner will consist of coarser `mesh wire next to the heat cham-ber andbecoming progressively liner mesh the more remote the screen layers arepositioned from the heat chamber.

The number of screen layers required in a particular lining ydepends onseveral variables such as the temperatures required to be produced inthe furnace, the type and size of the changes which the furnace isrequired to accommodate, the type of material lfrom which thescreens areconstructed, the type of insulation material between the screen linerand the outer wall, and other 'minor considerati-ons obvious to oneskilled in the art.

The type of screen material selected for the liner is governed by theheats to be produced. The melting point of the material must exceed thehigh heat level requirement of the furnace, oven, kiln or the like, inwhich the liner is to be used. Nichrorne and Inconal are trade names foralloys suitable for screening where the melting point of the screensmust be approximately 3,000 F. For higher temperature requirements thescreens can be ma-de from other metallic, as well as non-metallicmaterials.

The principle of operation of the screen liner is that due to the natureof construction of screening, much greater radiating surface ispresented than the equivalent area of conventional fiat, continuoussurface liners. The greater surface radiates and re-radiatm a greateramount of the heat produced in the heating chamber, thereby, raising theheat of the charge with relatively little heat loss.

The advantages derived rom use of a screen liner are many. An oven orfurnace using a conventional fiat, continuous surface type line-r cannotexceed heats -above approximately 800 F. without adding expensive, bulkyforced air blower apparatus, or Without heavy power consumption in lanelectric furnace. An oven or furnace using a screen liner can produceheats 4of approximately l700 F. Wit-hout adding a forced air blower orby using only a fraction of the power normally required in an electricfurnace. Also, a iurnace using the screen line of the pres-ent-invention is more economical to operate due to its greater eiciency andis less expensive initially because of the compactness of the ovendesign and the lighter weight Wall required to support the screenlliner. These economics of operation resulting :from the saving of uelor electric power are not limited to ovens and furnaces operating attemperatures above 800 F., brut can also be realized in ovens andfurnaces operating below 800 F. where the principle of radiation andre-radiation will reduce the ffuel or electric power consumed tomaintain a required temperature. Another advantage is a 'greatly reducedtime required to reach the desired heat, as Well as to cool d own thefurnace.

Various changes and .modcations will become apparent to one skilled inthe art in practicing the invention, however, .the invention includesall modifications and equivalents which fall within the scope of theappended claims.

I claim:

1. An apparatus adapted to produce heat comprising a housing having wallmeans arranged to define a chamber, said Wall means including a supportwall, insulation means disposed intermediate Said .support wall andchamber, and a lining disposed adjacent said insulation means andexposed to said chamber, said lining comprising multiple layers of heatresistant, mesh screens arranged in juxtaposition, and means for:heating said chamber Whereby heat in said chamber is absorbed :by saidlining and radiated lback intosaid chamber.

2. The apparatus delined in claim 1 wherein said screens are ofdiiferent mesh and aire arranged lwith .the coarser mesh screensdisposed closer to said chamber than the finer mesh screens.

3. The apparatus defined in claim 1 wherein said screens are ofprogressively liner mesh and are arranged with the screen having thecoarsest mesh disposed closest to said cham-her and the succeedinglayers of screens are of progressively finer meshV with the iinest meshscreen disposed most remote from said chamber.

4. The apparatus dened in claim 1 wherein said screens havesubstantially the saline mesh.

5. In lan apparatus adapted to produce heat land which includes wallsarranged to delinea heat chamber in which the heat is `adapted to beproduced, a liner for the chamber comprising multiple layers of lheatresistant, mesh screens arranged in juxtaposition 'and positionedrelative to said chamber to receive heat therefrom and radiate it backinto said chamber.

6. The apparatus as defined in claim 5 wherein said screens are ofprogressively finer mesh iand are arranged with the screen having theooarsest mesh closest to said chamber andthe succeeding layers ofscreens are of progressively finer mesh with the screen hav-ing thefinest mesh disposed `niost remote from said chamber.

7. The apparatus as defined in claim 5 wherein said screens havesubstantially -the same mesh.

References Cited by the Examiner UNITED STATES PATENTS 2,542,029 2/ 1951Hoffert 158-112 X 2,543,708 2/ 1951 Rice et tal. 263-40 X 2,607,6638/1952 Perry et al. 2,641,456 6/ 1953 Sohmertz 263-50 X 3,122,197 2/1964Saponara et ral.

FOREIGN PATENTS 727,174 3/ 1955 Great Britain. 852,457 10/1960 GreatBritain.

FREDERICK L. MATTESON, JR., Primary Examiner. JOHN J. CAMBY, Examiner.

5. IN AN APPARATUS ADAPTED TO PRODUCE HEAT AND WHICH INCLUDES WALLSARRANGED TO DEFINE A HEAT CHAMBER IN WHICH THE HEAT IS ADAPTED TO BEPRODUCED, A LINER FOR THE CHAMBER COMPRISING MULTIPLE LAYERS OF THEATRESISTANT, MESH SCREENS ARRANGED IN JUXTAPOSITION AND POSITIONEDRELATIVE TO SAID CHAMBER TO RECEIVE HEAT THEREFROM AND RADIATE IT BACKINTO SAID CHAMBER.